Achieving scratch resistance and flame retardancy in transparent polycarbonate through P/N/Si synergistic coating

Abstract

Transparent polycarbonate(PC) has attracted more and more attention due to its excellent properties, but it is still a challenge to give PC scratch resistance and flame retardancy while maintaining transparency. Herein, a transparent flame-retardant coating was successfully applied to PC using a phosphorus-containing organic amine curing agent (PETA), combined with epoxyoligosiloxane (AEOS) and epoxy resin (TGDDM). All samples showed high transparency and good scratch resistance, as well as good flame retardancy and fire resistance. The PEOS-TG-3 coating achieved a pencil hardness of 4H and an adhesion rating of 4B, demonstrating enhanced scratch resistance. The PHRR and THR of PC/PEOS-TG-3 was 21.4 % and 30.1 % lower than that of pure PC. Due to its simple synthesis method and effective char expansion, this P/N/Si synergistic flame-retardant coating holds significant potential for applications in flame-retardant protection for polycarbonate. This work demonstrates that the P/N/Si synergistic system not only guarantees the scratch resistance of PC sheets but also improves its flame retardancy while ensuring that the transparency is almost unaffected. This provides a feasible solution for the design and preparation of PC coatings with low cost, high flame retardancy and scratch resistance.